#define ROOT_HTML \
    "\
<head><meta charset='utf-8'></head>\
<script>var xhttp = new XMLHttpRequest();\
    function turnPage(page){\
        xhttp.open('GET', './turn_page?page='+page, true);\
        xhttp.send();\
    }\
</script>\
<center>\
    <h1>Hello from ESP32!</h1>\
    恭喜，你成功连接到ESP32的WiFi网络！</br>\
    <button style='width:300px; height:100px; font-size: 30px;' onclick='turnPage(\"/control\")'>控制页面</button></br>\
</center>\
"
// END =====================================================
